The present invention concerns a multi-cylinder engine and more particularly, relates to a multi-cylinder engine able to inhibit a common rail from being damaged.
There is a conventional example of the multi-cylinder engine which comprises a cylinder head having one lateral side surface onto which an intake-air distributing passage wall is attached and having the other lateral side surface onto which an exhaust-gas converging passage wall is attached, with a common rail arranged around the cylinder head as well as the present invention, on the assumption that a direction where a crank shaft spans is taken as a front and rear direction and that a widthwise direction of the cylinder head perpendicular to the front and rear direction is deemed as a lateral direction.
However, in the conventional multi-cylinder engine, the common rail is not sufficiently isolated from the cylinder head, as indicated in Japanese Patent Application Laid-Open (Kokai) No. 2001-227407 (see FIGS. 1 and 3), to result in entailing problems.
The conventional technique has the following problem.
<Problem> The common rail is easily damaged.
The common rail is not so sufficiently isolated from the cylinder head that combustion heat of the engine is readily conducted to the common rail. Thus the common rail is easily damaged by overheating.